1. Field of the Invention
The present invention relates to a power reception apparatus and a power transmission apparatus used in a power transfer system including the power reception apparatus that receives power from the power transmission apparatus in a contactless manner.
2. Description of Related Art
As a power transfer system using a power transmission apparatus and a power reception apparatus that transmit and receive power in a contactless manner, there are Japanese Patent Application Publication No. 2013-154815 (JP 2013-154815 A), Japanese Patent Application Publication No. 2013-146154 (JP 2013-146154 A), Japanese Patent Application Publication No. 2013-146148 (JP 2013-146148 A), Japanese Patent Application Publication No. 2013-110822 (JP 2013-110822 A), Japanese Patent Application Publication No. 2013-126327 (JP 2013-126327 A), Japanese Patent No. 5592242, and Japanese Patent Application Publication No. 2008-120239 (JP 2008-120239 A), and so on.
For example, a power reception apparatus described in Japanese Patent No. 5592242 includes an opening that is opened downward, a ferrite provided in a top plate of a shield, and a circular coil placed on a lower face of the ferrite.
Further, a power reception apparatus described in JP 2008-120239 A includes a substrate made of aluminum, a ferrite core provided on the substrate, and a coil wound around the ferrite core, and employs a configuration in which an outer periphery of the substrate overhangs an outer periphery of the ferrite core.
An outer peripheral end of the ferrite core employed in the power reception apparatus is placed on an inner side relative to an outer peripheral end of the shield in a plan view. That is, the outer peripheral end of the shield is placed on an outer side relative to the outer peripheral end of the ferrite core. On this account, at the time of power transfer in a power transfer system, a magnetic flux from the coil hits the shield, which may cause an eddy current loss. A power transmission apparatus may have a similar problem.